/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.io.hadoop.format;



import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.mapreduce.TaskAttemptID;

import org.apache.hadoop.mapreduce.TaskID;



import java.io.Serializable;



/**

 * Provides mechanism for acquiring locks related to the job. Serves as source of unique events

 * among the job.

 */

public interface ExternalSynchronization extends Serializable {



  /**

   * Tries to acquire lock for given job.

   *

   * @param conf configuration bounded with given job.

   * @return {@code true} if the lock was acquired, {@code false} otherwise.

   */

  boolean tryAcquireJobLock(Configuration conf);



  /**

   * Deletes lock ids bounded with given job if any exists.

   *

   * @param conf hadoop configuration of given job.

   */

  void releaseJobIdLock(Configuration conf);



  /**

   * Creates {@link TaskID} with unique id among given job.

   *

   * @param conf hadoop configuration of given job.

   * @return {@link TaskID} with unique id among given job.

   */

  TaskID acquireTaskIdLock(Configuration conf);



  /**

   * Creates unique {@link TaskAttemptID} for given taskId.

   *

   * @param conf configuration of given task and job

   * @param taskId id of the task

   * @return Unique {@link TaskAttemptID} for given taskId.

   */

  TaskAttemptID acquireTaskAttemptIdLock(Configuration conf, int taskId);

}